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AE Lock

May 14th, 2011 Andrei

Auto Exposure Lock (sometimes called AEL) is an excellent method of gaining added control over exposure, without losing the speed and convenience of automation. In fact, since most photographers today use some form of auto exposure the majority of the time, an understanding of how AE Lock operates can add a new dimension to their photography. This function offers something close to manual control over the exposure.

AE Lock Button on Canon

What is AE Lock?

What AE Lock does is simple: It “freezes” the camera’s exposure settings, so that if the camera is moved from one area to another, the auto exposure system won’t change aperture/shutter speed values. There are many situations where this may be useful. A photographer shooting a portrait, for example, might want to place the subject off-center. Taking a meter reading off the subject, locking it (along with focus), and then moving the camera to re-compose the subject means that exposure won’t shift if the background is lighter or darker than the subject itself. Another example might be a shooter taking a sequence of images, panning the camera from one area to another (following a moving subject, for example). If there are differences in the background or lighting, it’s possible that exposures will vary from one shot to the next. With AE Lock active, exposures would be consistent from shot to shot.

AE Lock On/Off

Auto Exposure Lock is a surprisingly useful tool that really expands what the photographer can do to apply exposure control, without losing the convenience and working speed of automatic exposure. In many cases, using it requires little more than identifying an element in a scene that you’d like to concentrate upon, aiming the camera at it and pressing the rear AE Lock button, and then re-composing to get the framing you want. It can lead to more consistent exposures when you’re shooting a sequence of shots, and is ideal for shooting with a primary subject off-center. It’s a great thing to get familiar with, so that you’re ready to use it when an opportunity presents itself.